Dampers for actuator assembly of hard disk drive

Abstract

An actuator assembly for a magnetic storage device includes a top surface and a bottom surface that opposes the top surface. The actuator assembly also includes a first constraining layer that is secured to the top surface by a first adhesive layer. The first adhesive layer is positioned between the top surface and the first constraining layer. Additionally, the actuator assembly includes a second constraining layer that is secured to the bottom surface by a second adhesive layer. The second adhesive layer is positioned between the bottom surface and the second constraining layer. At least one of (i) the first constraining layer is configured differently than the second constraining layer; and (ii) the first adhesive layer is configured differently than the second adhesive layer.

What is claimed is: 
     
       1. An actuator assembly for a magnetic storage device, comprising:
 at least one armature that supports a read-write head, wherein the at least one armature comprises a top surface and a bottom surface opposing the top surface; 
 a first constraining layer secured to the top surface by a first adhesive layer, the first adhesive layer being positioned between the top surface and the first constraining layer; and 
 a second constraining layer secured to the bottom surface by a second adhesive layer, the second adhesive layer being positioned between the bottom surface and the second constraining layer; 
 wherein at least one of (i) the first constraining layer is made from a first material and the second constraining layer is made from a second material that is different than the first material; and (ii) the first adhesive layer is made from a first adhesive and the second adhesive layer is made from a second adhesive that is different than the first adhesive. 
 
     
     
       2. The actuator assembly of  claim 1 , wherein the first and second constraining layers each comprises a rigid sheet. 
     
     
       3. The actuator assembly of  claim 2 , wherein the rigid sheet is made from a metallic material. 
     
     
       4. The actuator assembly of  claim 1 , wherein the first constraining layer has a first thickness and the second constraining layer has a second thickness that is different than the first thickness. 
     
     
       5. The actuator assembly of  claim 1 , wherein the first constraining layer has a first shape and the second constraining layer has a second shape that is different than the first shape. 
     
     
       6. The actuator assembly of  claim 1 , wherein the first and second adhesive layers are made from a same adhesive. 
     
     
       7. The actuator assembly of  claim 1 , wherein the first and second adhesive layers each is made from a visco-elastic adhesive. 
     
     
       8. The actuator assembly of  claim 1 , wherein the first and second adhesive layers have a lower stiffness than the first and second constraining layers, respectively. 
     
     
       9. The actuator assembly of  claim 1 , wherein the first adhesive layer has a first thickness and the second adhesive layer has a second thickness that is different than the first thickness. 
     
     
       10. The actuator assembly of  claim 1 , wherein the first adhesive layer has a first shape and the second adhesive layer has a second shape that is different than the first shape. 
     
     
       11. The actuator assembly of  claim 1 , wherein the first and second constraining layers are made from a same material. 
     
     
       12. The actuator assembly of  claim 1 , wherein the first constraining layer is made from a first material and the second constraining layer is made from a second material that is different than the first material, and the first adhesive layer is made from a first adhesive and the second adhesive layer is made from a second adhesive that is different than the first adhesive. 
     
     
       13. The actuator assembly of  claim 1 , wherein the first adhesive has different vibration damping characteristics than the second adhesive. 
     
     
       14. The actuator assembly of  claim 1 , wherein the first adhesive dampens vibrations more efficiently at higher temperatures than at lower temperatures, and wherein the second adhesive dampens vibrations more efficiently at lower temperatures than at higher temperatures. 
     
     
       15. A magnetic storage device, comprising:
 at least one magnetic disk; 
 at least one armature rotatably movable relative to the at least one magnetic disk, the at least one armature comprising a first surface and a second surface opposing the first surface; 
 a first vibration damper secured to the first surface, the first vibration damper comprising a first constraining layer and a first adhesive layer positioned between the first surface and the first constraining layer; and 
 a second vibration damper secured to the second surface, the second vibration damper comprising a second constraining layer and a second adhesive layer positioned between the second surface and the second constraining layer; 
 wherein at least one of (i) the first constraining layer is made from a first material and the second constraining layer is made from a second material that is different than the first material; and (ii) the first adhesive layer is made from a first adhesive and the second adhesive layer is made from a second adhesive that is different than the first adhesive. 
 
     
     
       16. The magnetic storage device of  claim 15 , wherein the first adhesive has different vibration damping characteristics than the second adhesive. 
     
     
       17. The magnetic storage device of  claim 15 , wherein the first adhesive dampens vibrations more efficiently at higher temperatures than at lower temperatures, and wherein the second adhesive dampens vibrations more efficiently at lower temperatures than at higher temperatures. 
     
     
       18. An apparatus for damping vibrations in an actuator assembly for a magnetic storage device, the actuator assembly comprising at least one armature comprising a top surface and a bottom surface opposing the top surface, the apparatus comprising:
 a first rigid sheet secured to the top surface by a first visco-elastic adhesive, the first visco-elastic adhesive being positioned between the top surface and the first rigid sheet; and 
 a second rigid sheet secured to the bottom surface by a second visco-elastic adhesive, the second visco-elastic adhesive being positioned between the bottom surface and the second rigid sheet; 
 wherein at least one of (i) the first rigid sheet is made from a first material and the second rigid sheet is made from a second material that is different than the first material; and (ii) the first visco-elastic adhesive is made from a first adhesive and the second visco-elastic adhesive is made from a second adhesive that is different than the first adhesive. 
 
     
     
       19. The apparatus of  claim 18 , wherein the first visco-elastic adhesive has different vibration damping characteristics than the second visco-elastic adhesive. 
     
     
       20. The apparatus of  claim 18 , wherein the first visco-elastic adhesive dampens vibrations more efficiently at higher temperatures than at lower temperatures, and wherein the second visco-elastic adhesive dampens vibrations more efficiently at lower temperatures than at higher temperatures.